As the core control element in hydraulic servo system, the resolution of servo valve directly affects the control accuracy and response performance of the system. In the fields of high-precision automation equipment, aerospace, robot and so on, the resolution of servo valve is required more and more. Therefore, it is of great theoretical significance and practical application value to study how to improve the resolution of servo valve.
First, the definition and influencing factors of servo valve resolution
The resolution of servo valve refers to its ability to produce detectable output changes with minimum input signal changes, usually expressed as percentage or micron displacement. The higher the resolution, the more sensitive the servo system is to the tiny signal and the more accurate the control is.
The main factors affecting the resolution of servo valve include:
1. Machining accuracy of valve core and valve sleeve: excessive clearance or substandard surface roughness will cause hysteresis and reduce resolution.
2. Linearity and sensitivity of electromagnetic drive components: for example, the response characteristics of torque motor or proportional electromagnet directly affect the controllability of spool displacement.
3. Cleanliness and viscosity characteristics of hydraulic oil: Excessive impurities or viscosity will lead to valve core sticking and increase friction resistance.
4. Noise and resolution of control signals: The accuracy and stability of analog or digital control signals will also affect the final resolution of the valve.
5. Temperature change and thermal expansion of materials: thermal deformation may cause structural gap change and affect the accuracy of valve core action.
Second, technical measures to improve the resolution of servo valve
1. Optimize the design and processing technology of valve core and valve sleeve.
Precision grinding and ultra-precision machining technology are adopted to improve the matching accuracy of valve core and valve sleeve and reduce the gap. At the same time, wear-resistant and corrosion-resistant materials, such as stainless steel and ceramic coating, are used to reduce the resolution degradation caused by wear in long-term use.
2. Improve the performance of electromagnetic drive components.
Use high sensitivity, low hysteresis torque motor or proportional electromagnet to ensure a good linear relationship between input signal and spool movement. In addition, a digital electromagnetic driver can be introduced to improve the signal processing ability and control accuracy.
3. Introduce closed-loop feedback control technology.
The position or flow sensor is integrated in the servo valve to form a closed-loop control system, which can detect the position of the spool in real time and make feedback adjustment, thus effectively compensating the nonlinear error and external interference and significantly improving the resolution.
4. Improve the quality of hydraulic oil and filtration system.
Use hydraulic oil with high cleanliness and appropriate viscosity, and configure high-precision filter device to prevent tiny particles from entering the valve core area and causing blockage or wear, and maintain the flexibility of valve core action.
5. Adopt digital control and intelligent algorithm.
The servo valve is matched with PLC or digital controller, and advanced algorithms such as PID control, fuzzy control or neural network are used to realize the fine processing of input signals, thus improving the overall resolution and response speed of the system.
6. Environmental adaptability design
The temperature compensation design of servo valve is carried out, and the thermal expansion factor is considered in material selection and structural design to ensure the stable working performance under different working conditions.
III. Conclusion
Improving the resolution of servo valve is a systematic project, involving mechanical design, material selection, control strategy and many other aspects. With the increasing demand for intelligent manufacturing and high-precision control, servo valves are developing towards high resolution, high reliability and intelligence. By optimizing structural design, improving driving performance, and introducing closed-loop control and digital technology, the working accuracy of servo valve can be effectively improved to meet the urgent demand of modern industry for high-performance hydraulic control system. In the future, with the continuous application of new materials, new processes and advanced control algorithms, the resolution of servo valves is expected to achieve greater breakthroughs.